--:-- [Upbeat music fades out]
--:-- Sean Rameswaram: The weather outside can be frightful, and KiwiCo wants to help you make your kids' holiday season delightful. They've got these projects that'll encourage learning about science and technology and math and art. Your kid gets to build them. They even have a couple of projects that you, an adult person, might enjoy. You can start your KiwiCo experience for free at KiwiCo.com slash explained.
--:-- Brian Resnick: Brian Resnick, you report on the sciences here at Vox, and I hear you have big, breaking scientific news for us this Friday. The news isn't just big, Sean. It's massive. Tell me more. What has happened?
--:-- Sean Rameswaram: Scientists have met in Versailles, France, and have voted to redefine the kilogram. And these changes will take effect next year.
--:-- Brian Resnick: The kilogram, like the weight? All right. So how do I explain this? What do you think a kilogram is?
--:-- Sean Rameswaram: I grew up in Canada. It's a whole lot of grams. Yeah, it's 1,000 grams. Okay. But do you know, like, what it is? Like, what's the definition of a kilogram?
--:-- Brian Resnick: No, I don't know more than, like, 1,000. Let me think here. I mean, I could tell you how much in, like, weed, I guess.
--:-- Sean Rameswaram: Well, really, a kilogram is a real physical object, and it's in France. It's a thing? It's a literal weight that's kept under three bell jars outside of Paris. It was created in the late 1800s to be this permanent representation of weight that the whole entire world can use.
--:-- Brian Resnick: What does it look like? Well, it's about an inch and a half, two inches high. It's like a hockey puck. Yeah, it's made out of a shiny metal and it weighs exactly a kilogram.
--:-- Sean Rameswaram: Okay, so why are they redefining this classic thing? Why not leave it be?
--:-- Brian Resnick: Because the kilogram right now is really kind of frustratingly imperfect. So if anything happens to that IPK, that international kilogram standard in France, all the other kilogram standards across the world have to adjust. Since this thing was created, scientists think it's lost about 50 micrograms, which is about the weight of an eyelash, which is really basically nothing.
--:-- Sean Rameswaram: But everything else now has to adjust to meet the international standard, that thing that's housed outside of Paris. A few atoms of air can stick to it. It maybe accidentally gets scratched and it loses some material.
--:-- Brian Resnick: You want these units to be anchored to things that are constant.
--:-- Sean Rameswaram: This cylindrical object upon which the kilogram is based, or it is the kilogram. It is the kilogram.
--:-- Brian Resnick: So what are the practical implications of this, that the kilogram is changing and it needs to be updated?
--:-- Sean Rameswaram: So right now, you need to go to Paris. You need to go to the U.S. government to verify what a kilogram is. It's something that's guarded under lock and key. It's something that needs to be verified.
--:-- Brian Resnick: So what's changing is actually like a kind of a democratization of the kilogram, where it will just be fixed to the fundamental truth of the universe.
--:-- Sean Rameswaram: How are they going to define this new kilogram?
--:-- Brian Resnick: So it turns out it's really complicated. I went to the National Institute of Standards and Technology, which has scientists that have been working on this redefinition for decades to help me understand it.
--:-- Sean Rameswaram: Can I come with you?
--:-- Brian Resnick: Of course. All right. Here we are at NIST. The National Institute of Standards and Technology, they have a campus in Gaithersburg, Maryland. We took an elevator down. We're about 12 meters below or 40 feet below. And these are the special labs that are most isolated.
--:-- Sean Rameswaram: So this is the place where they store the United States' copy of the master kilogram.
--:-- Brian Resnick: So, like, there are three keys you need to get into it. And these standard kilograms are basically the final verdict on, like, what a kilogram is in the United States.
--:-- Sean Rameswaram: You're, like, you are the keeper of... I'm the guy. You're the guy. But, like, the keeper of mass. I am. I am.
--:-- Brian Resnick: Is someone trying to steal the kilogram or something? Is this like National Treasure 3, the kilogram?
--:-- Sean Rameswaram: It's 40 feet below the Earth because, you know, when they make measurements of this thing, they don't want, like, any vibrations. They want it, like, super isolated.
--:-- Brian Resnick: They want to, like, make a really pristine environment to not just store this thing, but to measure it because we're comparing every single other weight measurement in the United States against these things. And we only have, like, seven of them.
--:-- Sean Rameswaram: One of them, which I saw, which is called K4, is made from the exact same metal that the original is made out of. So it's like its sister.
--:-- Brian Resnick: The real reason I was at NIST was to see this really massively, awe-inspiringly complicated machine.
--:-- Sean Rameswaram: But first I had to put on a hairnet and booties. We have to be clean, which means we've got to put on booties and a jacket and a little cap.
--:-- Brian Resnick: In this room, like, what is the fear if we don't do this? Contaminating the masses and adding mass to them.
--:-- Sean Rameswaram: And then that would add mass to everything?
--:-- Brian Resnick: That's correct. That's very, okay, I'm going to be very careful in here.
--:-- Sean Rameswaram: Once I had this gear on, I was able to go see this beautiful machine, which makes the redefinition of the kilogram possible.
--:-- Brian Resnick: What is the thing? It's called a kibble balance.
--:-- Sean Rameswaram: The kibble balance? The kibble balance.
--:-- Brian Resnick: It used to be called a watt balance, and it does something kind of crazy.
--:-- Sean Rameswaram: One of the scientists there, Doreen El-Haddad, explained it to me.
--:-- Brian Resnick: So you can see, as you told, we have a 60-ton concrete block, but you can see it's separate from the wall in the lab, so it and the whole thing can float.
--:-- Sean Rameswaram: It like a thing out of HG Wells
--:-- Brian Resnick: It has this great wheel at the top. It has lasers. It has magnets.
--:-- Sean Rameswaram: Can I like Google it? Can I see it somewhere?
--:-- Brian Resnick: Yeah, let me show you some pictures. Oh, my gosh, look at this thing. It looks like something out of, like, a brewery, if you've ever been to the back of a brewery and seen all the, like, tanks and the vats, but way more technical.
--:-- Sean Rameswaram: There's, like, copper pipes and all these little wheels everywhere. Yeah, it looks like if a brewery was capable of time travel.
--:-- Brian Resnick: Yes, that's it! This is what you'd imagine. Doc Brown is going to run out any second with some gasket blown.
--:-- Sean Rameswaram: I still need to explain why the kibble balance is so important. And I think to do so, we should talk about light speed and the meter.
--:-- Brian Resnick: It used to be the meter was literally just a metal pole in France.
--:-- Sean Rameswaram: The meter, too, was a thing in France? It was a thing in France. Wow.
--:-- Brian Resnick: What scientists did in the 80s is they redefined the meter to be the distance light travels in a vacuum, like, over a certain amount of time.
--:-- Sean Rameswaram: I think it's like one 300 millionth of a second or something like that is a meter.
--:-- Brian Resnick: They were baking in the definition of the meter to our understanding of the speed of light.
--:-- Sean Rameswaram: You take the meter, and suddenly it's something permanent. We know the speed of light, we know it doesn't change.
--:-- Brian Resnick: And then we just decided that some proportion of the speed of light is a meter, and now the meter never changes.
--:-- Sean Rameswaram: So how does that relate back to the kilogram?
--:-- Brian Resnick: Basically what they're doing here is something similar. They're affixing the kilogram to something that's called the Planck constant.
--:-- Sean Rameswaram: The Planck constant. The Planck constant.
--:-- Brian Resnick: The Planck constant. This is actually quantum mechanics. It basically describes how energy works and really small bits of matter.
--:-- Sean Rameswaram: Okay. What's important, though, is the Planck constant will never change. It's like the speed of light.
--:-- Brian Resnick: Wherever you go, it's true.
--:-- Sean Rameswaram: So this is where the kibble balance comes in. It allows us to define the Planck constant, but also allows us to make sure our understanding of the kilogram is tied to the Planck constant in the same way that our understanding of the meter is fixed to the speed of light.
--:-- Brian Resnick: The scientists I was talking to they were saying this is the most exciting moment of their career and this whole quest to find a way to make sure our measurements are attached to the things in the universe that will never change is actually kind of beautiful.
--:-- Sean Rameswaram: One of the scientists was describing to me they know this is technically a lot more complicated but philosophically it's a lot simpler. It's basically asking the universe, like, what are the stable things? And then we base our measurements off of the stable things in the universe.
--:-- Brian Resnick: So the meter is permanently tied to the speed of light, and now the kilogram is permanently tied to this mathematical concept, the Planck constant.
--:-- Sean Rameswaram: How should I picture it? Like, how should I picture the Planck constant?
--:-- Brian Resnick: One of the scientists I talked to actually had the Planck constant tattooed on his arm.
--:-- Sean Rameswaram: What does it look like? I have a picture of it.
--:-- Brian Resnick: Oh my god. It's like the most complicated equation tattoo I've ever seen.
--:-- Sean Rameswaram: It's probably the only equation tattoo I've ever seen.
--:-- Brian Resnick: H equals 6.62607015 times 10 to the negative 34. And then it says JS. Yeah, joule seconds is energy times time.
--:-- Sean Rameswaram: And under the tattoo you've got on this guy's arm, it says in French cursive, A tout le temps? A tout le peuple?
--:-- Brian Resnick: Yeah, for all times, for all people.
--:-- Sean Rameswaram: Wow. That's the founding motto of the metric system, which became the International System of Units.
--:-- Brian Resnick: Okay. That's why they love this work, because when you attach something like the kilogram to a constant of nature, you basically unleash it from the vault outside of France.
--:-- Sean Rameswaram: So right now, if you're an airplane manufacturer, it's really important to know how much an airplane weighs, so you want to make sure all your scales are calibrated right.
--:-- Brian Resnick: In the future, they won't have to go to a place like NIST to calibrate their scales. They could just have a kibble balance on their factory floor and determine precisely what a kilogram is because it's not something under lock and key anymore.
--:-- Sean Rameswaram: It's just like a truth of the universe.
--:-- Brian Resnick: Brian, you said earlier that they were democratizing weight, but now, like, I really see that you meant it.
--:-- Sean Rameswaram: Yeah, absolutely. You don't have to rely on a government anymore to tell you what something weighs. A kilogram is now baked into our definition of one of the constants of the universe.
--:-- Brian Resnick: Now the kilogram will never change because it's so closely tied to the Planck constant. The meter will never change because it's so closely tied to the speed of light.
--:-- Sean Rameswaram: It's like almost transcendent. Like you take our messy humanness and we've kind of made it permanent and celestial even.
--:-- Brian Resnick: I know a lot of the science can sound really complicated, but the simple part of it is that these scientists, their work is about finding the constant things in the universe that will never change.
--:-- Sean Rameswaram: The things that we can depend on year after year, century after century, perhaps even when the earth is no longer around.
--:-- Brian Resnick: If you think of all the things in the world that are just so topsy-turvy, that are just so not stable, it's really nice that there are people whose work is dedicated to finding the things that will never change.
--:-- Sean Rameswaram: There's definitely a beautiful purpose to that.
--:-- Brian Resnick: Next up we going to go back in time to a world before the kilogram.
--:-- Sean Rameswaram: I Sean Ramas This is Today Explained Alright, Vanderploeg. That's me.
--:-- Sean Rameswaram: Yeah. Hey, so you're the youngest person on staff here at Today Explained.
--:-- Vanderploeg: So I was wondering if you could be my stand-in for a small child and open up this gift that KiwiCo has sent us.
--:-- Sean Rameswaram: And I want to get your reaction to find out how impressed a young person would be by a KiwiCo project.
--:-- Vanderploeg: People often describe me as childish, childlike.
--:-- Sean Rameswaram: Yeah.
--:-- Vanderploeg: So, yes. Good. Open it, open it. Just go for it.
--:-- Sean Rameswaram: So this is the box within the box.
--:-- Vanderploeg: Whoa. Are these paints? No big deal. Various craft-like things. Okay. There's cardboard. There's, like, foam. Good. There's, uh, these are, like, these little cotton ball-y things of different colors.
--:-- Sean Rameswaram: You've got blue and green cotton ball-y things.
--:-- Vanderploeg: Oh, look at this beautiful little book. It says, Explore, a magazine to experiment, learn, and play. How delightful.
--:-- Sean Rameswaram: What's the title of that particular one?
--:-- Vanderploeg: Whale Tales. Mm, sounds nice.
--:-- Sean Rameswaram: This looks like it's salt. Oh, good. It says, Not for food use. Do not consume. Yeah, it is salt. Oh. Oh, oh, I see.
--:-- Vanderploeg: See, all of this comes together to build a mechanical sweeper that looks like a whale.
--:-- Sean Rameswaram: What do you think of that? I mean, it's pretty cool.
--:-- Vanderploeg: Kiwico.com slash explained.
--:-- Sean Rameswaram: What did you just do? Remember blogs?
--:-- Linda Anderman: Still has one. My most popular blog post of all time, which has gotten more than 150,000 page views, is the top 10 reasons why the U.S. should switch to the metric system.
--:-- Sean Rameswaram: Her blog's called More Than a Mile Behind, America and the Metric System.
--:-- Linda Anderman: You know, I've been writing about this topic for six years, and I've gotten over 300,000 page views, and only one person has called me a bitch so far.
--:-- Sean Rameswaram: Linda's also writing a book about this stuff. It's called America's Biggest Miscalculation.
--:-- Linda Anderman: She is obsessed with measurement.
--:-- Sean Rameswaram: When you're dealing with a subject that goes back tens of thousands of years, there's quite a bit of material.
--:-- Linda Anderman: What happened before we had this fancy kilogram out there in Paris? What was humanity using to measure everything before that?
--:-- Sean Rameswaram: A lot of things were based on body parts.
--:-- Linda Anderman: The definition of an inch was three barley corns taken from the center of the ear and placed end to end. And that was your inch.
--:-- Sean Rameswaram: You would actually measure fabric out. You would hold the cut end to your nose and then hold out your entire arm. And that would basically be used as a yard.
--:-- Linda Anderman: And, you know, a foot was a foot. But, like, it didn't matter that your foot was different than his foot and her foot and the small child's foot?
--:-- Sean Rameswaram: And that's the problem, isn't it?
--:-- Linda Anderman: So if you were measuring out fabric, you wanted the shortest person in your family to measure that fabric out.
--:-- Sean Rameswaram: Right.
--:-- Linda Anderman: And hands are still used with horses.
--:-- Sean Rameswaram: What do you mean? Horses don't have hands.
--:-- Linda Anderman: No, but you would measure how tall a horse was by hands.
--:-- Sean Rameswaram: You know, I even have a personal example of this that just came to mind.
--:-- Linda Anderman: And my mom would always tell me when I'm making rice, to measure how much water I should have, my water to rice ratio, I should fill the water until the first line on my finger.
--:-- Sean Rameswaram: And I still use that, even though it's totally imprecise and probably not the best way to make rice.
--:-- Linda Anderman: Yeah, you probably don't want your doctor dosing your medicine that way.
--:-- Sean Rameswaram: So how does this work for weight? I guess it's got to be a little different.
--:-- Linda Anderman: I mean, how did it work then for weight?
--:-- Sean Rameswaram: For a long time, people used balance scales to weigh things.
--:-- Linda Anderman: And so a merchant would have a standard that he would put on one side of the balance scale and then would measure things out and that's what you got.
--:-- Sean Rameswaram: You had to know that that standard hadn't been shaved off a little bit.
--:-- Linda Anderman: And in fact, merchants, because they were buying large amounts of material, they would actually have their own standard and would check their weights against the merchant's weight to make sure that they evened up.
--:-- Sean Rameswaram: Was that widespread, sort of cheating using counterweight and stuff like that?
--:-- Linda Anderman: Yeah, you know, there's so many ways to cheat with weights and measures.
--:-- Sean Rameswaram: And in fact, there are prohibitions in all of the major religious canons against cheating with weights and measures.
--:-- Linda Anderman: And that's why Lady Justice is blindfolded and holding a scale.
--:-- Sean Rameswaram: So how did all this start to change?
--:-- Linda Anderman: France was very advanced in terms of their scientific endeavors. In fact, the France Academy of Sciences began in 1666.
--:-- Sean Rameswaram: And because of the Age of Enlightenment that started in the 17th century, and the idea that it really wasn't evil spirits that were making the milk go bad, people started to rely on logic and reason.
--:-- Linda Anderman: And science was really starting to take off.
--:-- Sean Rameswaram: And it was recognized that science contains a lot of measurement.
--:-- Linda Anderman: And if scientists wanted to communicate their results to each other, they really needed to have one system that when they were talking about their units, they all knew what those units were.
--:-- Sean Rameswaram: Standards are things that people need. Nature doesn't need standards.
--:-- Linda Anderman: A river doesn't care how fast it's going and a flower doesn't care how tall it gets.
--:-- Sean Rameswaram: People need standards so that they can deal with each other.
--:-- Linda Anderman: So when does this hodgepodge of a system that might be different in every town you go to sort of start to coalesce into a real set of standards?
--:-- Sean Rameswaram: So 1790 was when three major countries, it was us, Thomas Jefferson and our country, the UK and France were all looking at metric based systems.
--:-- Linda Anderman: Jefferson was suspicious of the fact that this meter research was not going to be taking place on our soil.
--:-- Sean Rameswaram: But there has been resistance in this country for a long time.
--:-- Linda Anderman: The people who were against the metric system were really against the metric system.
--:-- Sean Rameswaram: Clearly Americans didn't like it.
--:-- Linda Anderman: Was it controversial in France?
--:-- Sean Rameswaram: Oh hell yeah
--:-- Linda Anderman: Hell yeah
--:-- Sean Rameswaram: And it still is in this country
--:-- Linda Anderman: But you know at some point people had to change over, particularly in France, where this really, you know, took off. It was legislated. I mean, you really didn't have a choice.
--:-- Sean Rameswaram: And obviously, it never worked out in America.
--:-- Linda Anderman: What did the United States miss out on as a result?
--:-- Sean Rameswaram: We don't realize how complicated we've made our lives by not using the metric system.
--:-- Linda Anderman: People are dying in this country because we don't use the metric system. I mean that very, very literally.
--:-- Sean Rameswaram: The Emergency Care Research Institute came out with the top 10 patient safety concerns for healthcare organizations.
--:-- Linda Anderman: And number seven was medication errors related to pounds and kilograms.
--:-- Sean Rameswaram: Because doctors and nurses are constantly going back between pounds and kilograms because the metric system is a basis for all science and medicine across the world.
--:-- Linda Anderman: Which is to say, even in the United States, our scientists are doing their work in the metric system.
--:-- Sean Rameswaram: Yeah. And that's part of the problem because if a doctor is writing that prescription in milliliters and if you go and pick up your prescription and it's got teaspoons and tablespoons on it, there's been a conversion.
--:-- Linda Anderman: And wherever there's a conversion, there's a potential for conversion error.
--:-- Sean Rameswaram: Just a couple of months ago, some medicine, the outer packaging, had one set of units on it, and the little cup on the inside had other units on it.
--:-- Linda Anderman: And they had to pull their product off the shelves because of it.
--:-- Sean Rameswaram: Are there other ways the U.S. system's holding us back?
--:-- Linda Anderman: We actually did send a probe to Mars, and we smashed it into the surface of the planet.
--:-- Sean Rameswaram: The Mars polar lander was to have given mankind its first look at the red planet's southern pole.
--:-- Linda Anderman: But as it descended, a computer onboard signaled that it had already landed.
--:-- Sean Rameswaram: The main engine switched off prematurely, and Mars became the recipient of one of the most expensive piles of scrap metal in space history.
--:-- Linda Anderman: Because even though the contract itself called for metric units, we were working in U.S. customary units, and as a result of that, there was a translation error.
--:-- Sean Rameswaram: The Mars Orbiter is part of a $300 million project known as Mars Surveyor 98.
--:-- Linda Anderman: NASA's latest in a series of relatively inexpensive attempts to mock underfunded public schools.
--:-- Sean Rameswaram: Linda, why do we do things that don't make sense?
--:-- Linda Anderman: Well, you know what? You need a mental health professional to address part of that.
--:-- Sean Rameswaram: If killing people and crashing a probe into Mars isn't going to get us to convert, I'm guessing the fact that we now have a precisely defined democratic universal kilogram ain't going to do it either, huh?
--:-- Linda Anderman: Well, yeah, here's how I fundamentally look at it. If you don't know how a change is going to affect you, the knee-jerk reaction is to reject that change.
--:-- Sean Rameswaram: And when you're talking about something that's as fundamental as measurements, people get twitchy because they're afraid that it's going to be difficult to do.
--:-- Linda Anderman: And it really isn't. I mean, you know, a quart and a liter are about the same size.
--:-- Sean Rameswaram: There's roughly two kilometers in a mile.
--:-- Linda Anderman: And the difference between a meter and a yard is only three inches.
--:-- Sean Rameswaram: They were trying to get my mother to change to the metric system.
--:-- Linda Anderman: My mother hadn't even been on the Internet by the time she died at 88.
--:-- Sean Rameswaram: But our kids don't expect anything to stay the same from one minute to the next.
--:-- Linda Anderman: So the rate of change has accelerated so much, I think it would actually be much, much easier to implement now than it would have been back in the 70s.
--:-- Sean Rameswaram: We're wasting an unbelievable amount of time for our kids in school, teaching them two systems, one of which nobody else uses, because nobody else uses U.S. customary units. It's just us.
--:-- Linda Anderman: Linda Anderman is working on a book on the history of the metric system. It's called America's Biggest Miscalculation.
--:-- Sean Rameswaram: She also blogs. I've gotten over 300,000 page views.
--:-- Linda Anderman: I'm Sean Ramasveram. This is Today Explained.
--:-- Sean Rameswaram: Irene Noguchi is weighing her options.
--:-- Linda Anderman: Bridget McCarthy is waiting on the world to change.
--:-- Sean Rameswaram: Afim Shapiro is bloodthirsty. He loves to kilogram.
--:-- Linda Anderman: Noam Hassenfeld can't wait.
--:-- Sean Rameswaram: Luke Vanderplug loves pound cake.
--:-- Linda Anderman: Catherine Wheels is way out of line.
--:-- Sean Rameswaram: Anna Altman's favorite sculptor is Ai Wei Wei
--:-- Linda Anderman: The massive Breakmaster Cylinder makes music for us and you should wait and review us on Apple Podcasts
--:-- Sean Rameswaram: Today Explained is produced in association with Stitcher and we're part of the Vox Media Podcast Network
--:-- Linda Anderman: The news isn't just big, Sean. It's massive.
--:-- Sean Rameswaram: Did you get the pun? Of course I got the pun.
--:-- Linda Anderman: Listeners don't know it's a pun yet, Brian.
--:-- Sean Rameswaram: Brian! Brian!
--:-- Linda Anderman: Thanks again to KiwiCo for supporting the show this week.
--:-- Sean Rameswaram: KiwiCo makes projects for your kids this holiday season. They've got all sorts of different ones.
--:-- Linda Anderman: They'll start coming in the mail if you subscribe. You can get a free trial when you go to kiwico.com slash explained k-i-w-i-c-o dot c-o-m slash explained
--:-- Sean Rameswaram: Spencer hall you're the host of sb nations it seems smart podcast from the vox media podcast network
--:-- Linda Anderman: We talked yesterday about the newest episode in the feed but what else can people hear in there
--:-- Sean Rameswaram: Well they can hear episode two if they like and I encourage them to because it covers the legendary cannonball run
--:-- Linda Anderman: We talked to the current record holder for the unsanctioned unlicensed and possibly illegal transcontinental race from New York to Los Angeles
--:-- Sean Rameswaram: Guy named Ed Bowling lives here in Atlanta, and he managed to do it with two people he barely knew in a car in, oh, you know, under 30 hours straight.
--:-- Linda Anderman: Nuts. Okay, cool. And that episode's in the feed right now.
--:-- Sean Rameswaram: Yeah, that's in the feed right now. Go ahead. Put it in your ears.
--:-- Linda Anderman: Great. It seems smart wherever you find your podcasts.
